Synergistic Promotion of Single-Atom Co Surrounding a PtCo Alloy Based on a G-C3n4 Nanosheet for Overall Water Splitting

Atomically dispersed catalysts with maximum efficiencies for atom utilization have emerged as a frontier in the catalytic field. However, single- component monatomic catalysts are rarely reported for the overall photocatalytic water splitting reaction (OWS). Herein, a two-component synergistic photocatalyst was designed that contained a dispersion of single-atom Co (Co-SAs) centers and PtCo alloy nanoparticles (Nps), which were supported over C3N4 nanosheets. Among these components, Co-SAs centers act as highly active sites for the hydrogen evolution reaction (HER), and PtCo alloys act as highly active sites for the oxygen evolution reaction (OER). A synergistic effect between them occurs when the two different reactive centers are combined, indicating that there may be a spillover phenomenon of protons or hydroxyl groups between the Co-SAs, centers and PtCo alloy NPs. The synergistic promotion of Co-SAs centers and PtCo alloys bridges the gap between achieving maximum atom utilization and optimal bifunctional activities for OWS reactions. This combination provides a promising model for the development of OWS by atomically dispersed catalysts.